多跨空心板简支梁连续化改造研究

发布时间：2018-08-14 09:08

【摘要】：随着交通量的日益增长,我国的许多简支梁桥在服役多年后出现伸缩缝破损的病害并诱发其他相关病害,严重影响交通服务功能,甚至危及交通安全和结构安全。虽然新型伸缩缝构造和材料不断出现,但是问题一直没有得到根本性的解决。为此,本文以既有多跨空心板简支梁的连续化改造为研究对象,以福建漳州十里桥为工程背景,对改造后全桥的整体受力性能、新旧混凝土结合面局部进行分析,并提出AHP(层次结构分析)数学模型对改造后支座选型进行优化分析。主要工作和研究内容如下：(1)依据福建漳州十里桥外观检测和环境脉动、动力响应试验的结果,对全桥进行现役承载力评定。并通过借鉴国内外经验,选择空心板梁简支连续化改造方案。(2)对多跨空心板梁简支连续化改造效应进行分析。连续化改造后,恒载作用下跨中正弯矩有所降低,最大降低26.4%；改造后活载承载能力提高较明显,活载提高值为改造前的1.45～1.65倍；连续化改造后,边跨最外侧的支座处剪力比改造前有降低了6.8%～7.6%；其余支座处的剪力要比改造前增大5.6%～8.4%。(3)基于Midas-FEA程序对空心板梁连续化改造墩顶处应力分析。结果表明由于墩顶正负弯矩的存在,引起支座处最不利位置处的最小主应力出现反弯现象,造成剪力抗力值不足,建议连续化改造设计时要重点复核支座处剪力。(4)通过有限元和理论计算,对连续化改造横向分布进行分析研究。结果表明连续化改造后,横向分布更加均匀,增强了主梁之间的协同作用,降低了单板受力的发生概率。(5)通过有限元程序计算,计算得出新旧混凝土龄期差引起的收缩徐变弯矩值为正弯矩,对跨中受力不利。跨中弯矩最大增幅为3.9%；缓和了墩顶负弯矩峰值和范围,负弯矩最大降低幅度约为4.3%,影响不明显。(6)利用Midas-FEA程序,对新旧混凝土结合面进行局部分析。连续化改造中,新旧混凝土结合面在收缩徐变、温度作用等荷载作用下能够协调的工作,但是新旧混凝土结合面处抗拉应力安全储备较低,建议设计改造时对此位置可以通过利用微膨胀混凝土、低收缩性材料或者采用机械方式进行局部补强。(7)利用层次分析法(AHP),从荷载效应、温度效应、施工条件、地质条件四个结构层次分析,建立单双支座选择方式的数学模型。通过建立的数学模型优化分析得出漳州十里桥简支连续化改造工程选择双支座。
[Abstract]:With the increasing traffic volume, many simply supported bridges in our country appear the damage of expansion joints after many years of service and induce other related diseases, which seriously affect the traffic service function, even endanger the traffic safety and structural safety. Although new expansion joint structures and materials continue to appear, but the problem has not been fundamentally resolved. Therefore, this paper takes the continuous reconstruction of the existing multi-span hollow slab simply supported beam as the research object, taking Zhangzhou Shili Bridge in Fujian as the engineering background, analyzes the overall mechanical performance of the whole bridge after the reconstruction and the part of the new and old concrete joint face. The AHP (hierarchical structure Analysis) mathematical model is put forward to optimize the support selection after the transformation. The main work and research contents are as follows: (1) the bearing capacity of the whole bridge is evaluated according to the results of exterior inspection, environmental pulsation and dynamic response test of Zhangzhou Shili Bridge in Fujian Province. By using domestic and foreign experience for reference, the continuous reconstruction scheme of simple support of hollow slab beam is selected. (2) the effect of continuous reconstruction of simple support of multi-span hollow slab beam is analyzed. After continuous transformation, the positive bending moment of span under the action of dead load decreases to a certain extent, and the maximum reduction is 26.4.The load carrying capacity of live load increases obviously after the transformation, and the improvement value of live load is 1.45 ~ 1.65 times of that before transformation. The shear force at the outermost support of the side span is reduced by 6.87.6and the shear force at the rest of the support is increased by 5.68.4. (3) the stress at the top of the continuous reconstruction of hollow slab beam is analyzed based on the Midas-FEA program. The results show that due to the existence of positive and negative moment at the top of the pier, the minimum principal stress at the most unfavorable position of the support appears reverse bending phenomenon, which results in the insufficient value of shear resistance. It is suggested that the shear force at the support should be reviewed when designing the continuous transformation. (4) the transverse distribution of the continuous transformation is analyzed and studied by finite element method and theoretical calculation. The results show that after the continuous transformation, the transverse distribution is more uniform, the synergy between the main beams is enhanced, and the probability of the stress on the veneer is reduced. (5) the finite element program is used to calculate, The results show that the shrinkage and creep moment caused by the age difference of new and old concrete is positive moment, which is unfavorable to the stress in the middle of span. The maximum increment of mid-span moment is 3.9, the peak value and range of negative moment at the top of pier are alleviated, the maximum decrease of negative moment is about 4.3, and the influence is not obvious. (6) using Midas-FEA program, the local analysis of the new and old concrete joints is carried out. In the continuous transformation, the new and old concrete joints can work harmoniously under the action of shrinkage, creep and temperature, but the safety reserve of tensile stress at the new and old concrete joints is low. It is suggested that this position can be partially strengthened by using micro-expansive concrete, low-shrinkage material or mechanical method. (7) Analytic hierarchy process (AHP),) is used to analyze the load effect, temperature effect and construction conditions. The mathematical model of the selection of single and double supports is established by analyzing the four structures of geological conditions. Through the optimization analysis of the established mathematical model, it is concluded that double supports are selected for the continuous reconstruction of the simple support of Zhangzhou Shili Bridge.
【学位授予单位】：福州大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U445.7

【相似文献】